I am trying to specify the number of times a trial should be played within a block.
I am doing this using a Macro within the Block Editor which repeats the block indefinitely (by leaving the expression empty, so it always evaluates to 'true') and then specifying how many times to play each trial within the Trial Editor ('present if number of times trial has been presented is...')

If I understand correctly, Superlab considers a trial to have been presented once every item in the stimulus list has been presented.. Is that correct? If so, is there a way to specify the number of repeats based on the number of times the trial (i.e., one individual stimulus) has been presented? Or will I have to either abandon my stimulus lists or set the number of items in the list to match the number of times I want the trial to be presented?

Perhaps a more simple question is: is it possible to only present a subset of a stimulus list? If so, how?

Yes, it is possible to specify the number of times that a trial can be repeated. But quite frankly, I no longer remember how this is done since it became a built-in feature in SuperLab 5 over four years ago.

As for presenting a subset of a stimulus list, it is much easier to do using the rules feature in SuperLab 5. But this too is now a built-in feature of the upcoming SuperLab 6, a beta release of which is being made available to users who need this feature.

We still support SuperLab 4, but with exceptions. Support resources are expensive, yet we provide them freely. But when the answer to a question is a simple “see Block Editor’s Looping tab”, it is not economical for us to spend time and create a workaround in an earlier version. Chances are that it’s not economical for you either.